Technical Field
The present disclosure relates to stable skin care compositions containing hydroquinone, chelating agents and methods for manufacturing them in specially treated steel vessels.
Background of the Invention
Hydroquinone inhibits the formation of melanin and pigmentation of the skin and, accordingly, has been found to be useful in skin care products, especially products designed to lighten the skin of a user. Unfortunately, hydroquinone compositions turn to a brown color as the hydroquinone in the composition is oxidized. The discoloration of the hydroquinone product is aesthetically undesirable and unacceptable to the consumer. Also, the oxidation by-products of hydroquinone may diminish its effectiveness and irritate the skin of a user.
Although various attempts have been made to solve the problem of discoloration of hydroquinone skin care compositions, applicants are unaware of any stabilized composition that provides the three year shelf-life that is desirable for consumer skin care products. Thus, there remains room for improvement in manufacturing hydroquinone skin care compositions, especially to provide hydroquinone skin care compositions that do not oxidize and discolor during shipment and storage and which exhibit a three year shelf-life.